Installing flue damper in double-wall chimney pipe?

[Armitage]

So I'm setting up a small woodstove in my addition to reduce my excuses for not finishing it ... you know ... like "it's to damn cold to work out there today" I'm using double wall duravent pipe to connect the stove to my triple wall duravent chimney. But nowhere in the instructions or pictures does it show anything installing a flue damper ... you know, that handle on the chimney pipe you use to control the draft.

Do I just drill it like a normal single wall pipe, or is there something special I need to do. Of course, the dealer I bought it from is closed today :roll:

 

[jonn]

depends, if its a large diameter pipe, can you get a damper that has a long enough thru shaft to work?
If so, it wont hurt to have one, better burn control.
Now if you have any single pipe below the triple wall, easy to put one in there too.
I have seen stoves not need a damper but there have to be very air tight or else they will get out of control
Also depends on what you are going to fuel it with on how hard it burns.

 

[Armitage]

I don't think I'll have any trouble finding one ... the double wall maybe adds 3/8" on each side. But I definitely want a damper on there, especially as we burn pine out here which can get hot fast. I don't think I've ever actually seen a wood stove without a flue damper?!

 

[sharkeeper]

Airtight stoves do not need a damper in the flue. You regulate the burn (always) by throttling the air at the doors. Only "loose" stoves such as Franklin and pot bellies really need a damper in the flue above the combustion chamber.

Burning resinous woods on a continuous basis is not recommended as if you attempt to bank down your fires - you will get a lot of creosote running too close to the combustion chamber. It only takes one hot burn to realise this and you have a chimney fire which is not fun.

Cheers!

 

[Spencer278]

Why would you use double-wall pipe inside? Don't you want the heat to get out into the room your trying to heat?

 

[woowoo]

Originally posted by: Spencer278
Why would you use double-wall pipe inside? Don't you want the heat to get out into the room your trying to heat?

To keep the flue gasses hot
Cold = condensate (Wet flue)

 

[sharkeeper]

To keep the flue gasses hot
Cold = condensate (Wet flue)

Yes a cold stack will result in buildup of creosote quickly which will insulate the flue and raise temps until it ignites and then you have a problem.

Cheers!

 

[ShotgunSteven]

Originally posted by: sharkeeper
Airtight stoves do not need a damper in the flue. You regulate the burn (always) by throttling the air at the doors. Only "loose" stoves such as Franklin and pot bellies really need a damper in the flue above the combustion chamber.

Burning resinous woods on a continuous basis is not recommended as if you attempt to bank down your fires - you will get a lot of creosote running too close to the combustion chamber. It only takes one hot burn to realise this and you have a chimney fire which is not fun.

Cheers!

No flue damper here, just the door vents. That reminds me, I probably need to clean the chimney again.

EDIT: Main fuels for the fire are spruce, birch, and sometimes some cottonwood for filler.

 

[Armitage]

Originally posted by: sharkeeper
Airtight stoves do not need a damper in the flue. You regulate the burn (always) by throttling the air at the doors. Only "loose" stoves such as Franklin and pot bellies really need a damper in the flue above the combustion chamber.

Really? I've never never heard this. We've been burning airtight stoves for years ... they've all had flue dampers.

Burning resinous woods on a continuous basis is not recommended as if you attempt to bank down your fires - you will get a lot of creosote running too close to the combustion chamber. It only takes one hot burn to realise this and you have a chimney fire which is not fun.

Yea, I've seen a chimney fire ... sounds like a jet engine test stand in your living room! Unfortunately, in the rockies, all you have is pine. Some aspen as well, but I'm not sure that's much better. Remarkably, when I clean the chimney for our fireplace insert, there has never been a significant creosote buildup ... certainly not like my dad's chimney back in PA where they burn nothing but hardwood. I think the dxifference may be that his chimney is outside the house, cold on 3 sides, while mines runs up the center of the house.

 

[Armitage]

Originally posted by: woowoo

Originally posted by: Spencer278
Why would you use double-wall pipe inside? Don't you want the heat to get out into the room your trying to heat?

To keep the flue gasses hot
Cold = condensate (Wet flue)

That and single wall pipe need 18" of clearance, which I don't have. With double wall, you only need 6" I designed the placement with that in mind to reduce the space taken up by the fireplace & chimney.

 

[sharkeeper]

Really? I've never never heard this. We've been burning airtight stoves for years ... they've all had flue dampers.

It's the norm with non airtight designs because it's a requirement. It's optional with airtight designs. Always check your code, however as some locales may require it to pass inspection!

Many people that burn with hardwood bank (choke off) their fires way down. Gets a good long burn and is recommended for best efficiency. There is a cycle to this process, however that must not be omitted. On every other burn you should add a sparse charge of wood and let it roar for a good 45 minutes or even longer. Flue temps soar and any deposits will burn off. If this hasn't been done in a while, it's best to go slow to avoid a fire. A small fire is inevitable sooner or later but the kind that shake the house from weeks of neglect are the ones you want to avoid!

You should have a flue thermometer as well. It's a good gauge of what's going on as a cold stack appears the same as a hot one unless it's really hot!

Cheers!

 

[Armitage]

Originally posted by: Armitage

Originally posted by: sharkeeper
Airtight stoves do not need a damper in the flue. You regulate the burn (always) by throttling the air at the doors. Only "loose" stoves such as Franklin and pot bellies really need a damper in the flue above the combustion chamber.

Really? I've never never heard this. We've been burning airtight stoves for years ... they've all had flue dampers.

Well, just got off the phone with the dealer, who confirmed what you said sharkeeper. They do hundreds of installs, and never use a flue damper, although they have a section you can buy with one in it.

Wierd ... it's just one of those things I'm not comfortable with. Since I was a little kid, my dad always harped on checking the flue damper before leaving the stove for the night, and that was an airtight stove also. Well, I guess I'll set it up and see how it goes.